A paramecium (Paramecium caudatum) is a very tiny
unicellular organism. Each paramecium is between 50 and
305μm (micrometers) long. They start out small and grow in
length as they mature. Paramecia (more than one
paramecium) are complex, or eukaryotic, cells, which makes
them part of the Protist kingdom.
You can find paramecia in warm, stagnant pond water,
usually in the scum that collects on the top of the water.
Paramecia are safe from most things that would eat them in
the pond scum, and they are able to find things to eat!
Paramecia eat bacteria, other unicellular organisms and
decaying plant matter. They are able to take in the oxygen
(O2) that is dissolved in pond water and give off carbon
dioxide (CO2) as a waste.
Paramecia are covered in tiny hair-like projections called cilia that help them
move around. The cilia wave in a rhythm that propels the cell through the water
it lives in. Paramecia are almost always moving. When a paramecium hits a
solid object, it turns and keeps going. Sometimes it has to turn several times to
get around a big object!
Being a eukaryotic cell, there are
many specialized parts to a
paramecium. They have an opening,
or oral groove, to take in food.
Special cilia around the oral groove
move the food into the cell. They also
have an anal pore to get rid of waste.
Paramecia like warm, liquid water and
are attracted to acidic conditions.
Acidic conditions tell them that there
might be food nearby. They are
sometimes eaten by another Protist known as an amoeba. Amoebas are bigger
than paramecia, and eat their food by surrounding it and making it part of its cell.
Luckily for paramecia, they are faster than amoebas!
Paramecia are able to reproduce sexually or asexually. Under normal
conditions, they usually reproduce asexually by a process called binary fission.
In binary fission, a unicellular organism splits in half to create two new
organisms! Paramecia reproduce sexually only when there is stress on the
population, such as not enough food.
http://acpcommunity.acp.edu/Facultystaff/moon/Biology1/Bacteria/Paramecium,%20200x.BMP
Information taken from http://microbewiki.kenyon.edu/index.php/Paramecium